Systems and methods for storing data to magnetic tape having damaged areas

ABSTRACT

A method for using magnetic tape having damaged areas is disclosed. The method may include writing data to streaming magnetic tape, determining if the data write was successful, and responding to an unsuccessful data write by interrupting the data writing and advancing the magnetic tape forward a predetermined distance. Additionally, the method may include attempting to write data at the next location on the magnetic tape and determining if the data write was successful. The method may further include repeating the steps of advancing the tape, attempting to write, and determining whether the data write was successful following any determination that an attempted data write was not successful. The method may include further include resuming writing data to streaming magnetic tape at a location where a data write is determined to be successful.

TECHNICAL FIELD

The present disclosure relates in general to magnetic tapes for use inan information handling system, and more particularly to storing data toa magnetic tape having damaged areas.

BACKGROUND

As the value and use of information continues to increase, individualsand businesses seek additional ways to process and store information.One option available to users is information handling systems. Aninformation handling system generally processes, compiles, stores,and/or communicates information or data for business, personal, or otherpurposes thereby allowing users to take advantage of the value of theinformation. Because technology and information handling needs andrequirements vary between different users or applications, informationhandling systems may also vary regarding what information is handled,how the information is handled, how much information is processed,stored, or communicated, and how quickly and efficiently the informationmay be processed, stored, or communicated. The variations in informationhandling systems allow for information handling systems to be general orconfigured for a specific user or specific use such as financialtransaction processing, airline reservations, enterprise data storage,or global communications. In addition, information handling systems mayinclude a variety of hardware and software components that may beconfigured to process, store, and communicate information and mayinclude one or more computer systems, data storage systems, andnetworking systems.

Magnetic tape data storage devices are commonly used with informationhandling systems to write, read, and store data. Since its introductionover fifty years ago, magnetic tape has remained a popular data storageformat despite the development of alternative media such as compactdisks, USB flash drives, memory sticks, and others. One beneficialfeature of magnetic tape is that it remains the most inexpensive andefficient means for storing or archiving large volumes of data. Withadvancing technology, high density magnetic tape has allowed forindividual tape devices to provide increasingly greater data storagecapacity. Further, large quantities of magnetic tape devices can behoused within automated tape libraries and serviced by shared read-writeunits, which allows for enhanced organization and rapid access of data.Additionally, magnetic tape allows for erasing and modifying data unlikemany other media formats, such as read-only compact disks.

To increase the data storage capacity in high density tape devices,advancing technology has made it possible to utilize increasinglythinner magnetic tape in tape storage devices. However, such thin tapeis often fragile, and thus susceptible to damage in the normal course ofuse. For example, edge damage, wrinkles, cupping, and compression creepare common with today's thinner tapes, despite the increasedsophistication of tape paths and tension methods within tape drives.

Given the present methods by which tape drives read and write tomagnetic tape, the likelihood of tape damage presents a drawback tostoring data to tape. Currently, a write head writes data to magnetictape and an error detection technique is then performed to determinewhether the data write was successful. Any damage or defect in themagnetic tape may result in data corruption, whereby the tape drive mayrespond by issuing a soft write error and may then re-attempt to writethe intended data. If the second attempt is unsuccessful, the tape drivemay issue a hard write or fatal error message and may abort read-writeoperations. This may occur at the damaged location each time data isattempted to be written to the tape regardless of how minimal thedamaged area is, or how much undamaged tape remains beyond the damagedarea. Thus, based on current methods, many high capacity magnetic tapecartridges are rendered unusable, and often discarded, despite retaininga large amount of unused data storage capacity.

SUMMARY

In accordance with the teachings of the present disclosure,disadvantages and problems associated with writing data to magnetic tapehaving damaged areas have been substantially reduced or eliminated.

In accordance with one embodiment of the present disclosure, a methodfor using magnetic tape having one or more damaged areas is provided.The method may include writing data to streaming magnetic tape,determining if the data write was successful, and responding to anunsuccessful data write by interrupting the data writing and advancingthe magnetic tape forward a predetermined distance. Additionally, themethod may include attempting to write data at the next location on themagnetic tape and determining if the data write was successful. Themethod may further include repeating the steps of advancing the tape,attempting to write, and determining whether the data write wassuccessful following any determination that an attempted data write wasnot successful. Furthermore, the method may include resuming writingdata to streaming magnetic tape at a location where a data write isdetermined to be successful.

In accordance with another embodiment of the present disclosure, a tapedrive for writing data to magnetic tape may include a tape headconfigured to write data, an error detection module configured to detecta data writing error, and a tape advancement module configured tointerrupt data writing and advance the tape forward a predetermineddistance to a next location on the magnetic tape in response todetecting a data writing error. Additionally, the tape head, the errordetection module, and the tape advancement module may be configured tocooperate to repeat the functions of advancing the magnetic tape apredetermined distance, attempting to write data to the magnetic tape,and determining if the attempted data write was successful followingeach unsuccessful data writing attempt. Further, the tape head may beconfigured to continue to write data to the magnetic tape at anundamaged location.

In accordance with a further embodiment of the present disclosure, aninformation handling system may include a processor and a tape drivecoupled to the processor. The information handling system may furtherinclude a tape drive including a tape head configured to write data, anerror detection module configured to detect a data writing error, and atape advancement module configured to interrupt data writing and advancethe tape forward a predetermined distance to a next location on themagnetic tape in response to detecting a data writing error. Further,the information handling system may include a tape drive wherein thetape head, the error detection module, and the tape advancement modulemay be configured to cooperate to repeat the functions of advancing themagnetic tape a predetermined distance, attempting to write data to themagnetic tape, and determining if the attempted data write wassuccessful following each unsuccessful data writing attempt.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present embodiments and theadvantages thereof may be acquired by referring to the followingdescriptions taken in conjunction with the accompanying drawings, inwhich like reference numbers indicate like features; and wherein:

FIG. 1 illustrates an example tape drive device for using magnetic tapehaving damaged areas, in accordance with certain embodiments of thepresent disclosure;

FIG. 2 illustrates a block diagram of an example information handlingsystem for using magnetic tape having damaged areas, in accordance withcertain embodiments of the present disclosure;

FIG. 3 illustrates a flow chart of an example method for using magnetictape having damaged areas, in accordance with certain embodiments of thepresent disclosure; and

FIG. 4 illustrates a flow chart of an example method for accessing tapelocation data and using such data to skip damaged areas of magnetictape, in accordance with certain embodiments of the present disclosure.

DETAILED DESCRIPTION

Preferred embodiments and their advantages are best understood byreference to FIGS. 1-4, wherein like numbers are used to indicate likeand corresponding parts.

For the purposes of this disclosure, an information handling system mayinclude any instrumentality or aggregate of instrumentalities operableto compute, classify, process, transmit, receive, retrieve, originate,switch, store, display, manifest, detect, record, reproduce, handle, orutilize any form of information, intelligence, or data for business,scientific, control, entertainment, or other purposes. For example, aninformation handling system may be a personal computer, a PDA, aconsumer electronic device, a network storage device, or any othersuitable device and may vary in size, shape, performance, functionality,and price. The information handling system may include memory, one ormore processing resources such as a central processing unit (CPU) orhardware or software control logic. Additional components or theinformation handling system may include one or more storage devices, oneor more communications ports for communicating with external devices aswell as various input and output (I/O) devices, such as a keyboard, amouse, and a video display. The information handling system may alsoinclude one or more buses operable to transmit communication between thevarious hardware components.

For the purposes of this disclosure, computer-readable media may includeany instrumentality or aggregation of instrumentalities that may retaindata and/or instructions for a period of time. Computer-readable mediamay include, without limitation, storage media such as a direct accessstorage device (e.g., a hard disk drive or floppy disk), a sequentialaccess storage device (e.g., a tape disk drive), compact disk, CD-ROM,DVD, random access memory (RAM), read-only memory (ROM), electricallyerasable programmable read-only memory (EEPROM), and/or flash memory; aswell as communications media such wires, optical fibers, microwaves,radio waves, and other electromagnetic and/or optical carriers; and/orany combination of the foregoing.

FIG. 1 illustrates an example tape drive device 100 for using a magnetictape 102 having damaged areas, in accordance with certain embodiment ofthe present disclosure.

Tape drive 100 may include a magnetic tape 102, a tape storage device104, a reel 106, a spool 108, a tape head 110, an error detection module112, a tape advancement module 114, rollers 116, a memory 118, anddamaged/undamaged-tape-location data 120. Tape drive 100 may begenerally configured to write data to and/or read data from magnetictape 102.

Tape storage device 104 may house magnetic tape 102. For example, tapestorage device 104 housing may include a Linear Tape-Open (LTO)cartridge or the like.

In some embodiments, reel 106 may be housed in tape storage device 104.Tape drive 100 may be configured to transfer magnetic tape 102 from reel106 onto spool 108 in a forward direction and/or from spool 108 ontoreel 106 in a reverse direction. A leader pin that interlocks with aleader block within tape storage device 104 may pull magnetic tape 102from the cartridge.

Tape head 110 may comprise one or more head elements, e.g., a read headelement and/or a write head element. In some embodiments, tape head 110may comprise a write head element that spatially precedes a read headelement in relation to the linear-forward-flow direction of magnetictape 102 advancement. Tape head 110 may be configured to write data tomagnetic tape 102.

Error detection module 112 may be configured to detect data writingerrors at various locations on magnetic tape 102.

Tape advancement module 114 may be configured to control movement andadvancement of the tape 102. Magnetic tape 102 may move linearly pastthe surface of tape head 110. Tape advancement module 114 may advancetape 102 by rotating either reel 106, spool 108, or both. Rollers 116may guide magnetic tape 102, keeping magnetic tape 102 in contact withtape head 110.

Each module 112, 114 may include any software, firmware, or hardwarenecessary to perform associated operations, functions, and tasks. Forexample, each module 112, 114 may include software, firmware, or logicstored on computer-readable media.

Memory 118 may be configured to store tape location data 120. Tapelocation data 120 may include data indicating physical locations onmagnetic tape 102 where a write error was detected and/or dataindicating physical locations on magnetic tape 102 where data writingwas successful.

In operation, error detection module 112 may be configured to detectdata writing errors at various locations on magnetic tape 102. In someembodiments, error detection module 112 may detect data writing errorsby comparing the data intended to be written to magnetic tape 102 withthe data actually written to magnetic tape 102 by tape head 110. Forexample, a read head element of tape head 110 may read data written tomagnetic tape 102 by a write head element of tape head 110, and errordetection module 112 may use this read data as the actual data writtento magnetic tape 102 for comparison purposes.

In certain embodiments, error detection module 112 may perform a CyclicRedundancy Check (CRC) for detecting a data write error. A CRC mayinclude taking a data stream as input and outputting a value of acertain fixed size. The CRC may be used as a checksum or redundancycheck to detect alterations of data during transmission or storage.

In some embodiments, error detection module 112 may include a ViterbiDetector to sample data tracks to assist in detecting a data writeerror. For example, a Viterbi Detector may include a Viterbi algorithmthat may include dynamic programming for finding the most likelysequence of hidden states that result in a sequence of observed events.The Viterbi algorithm may include a closely related algorithm forcomputing the probability of a sequence of observed events.

In response to error detection module 112 detecting a write error, tapeadvancement module 114 may be configured to interrupt data writing andadvance tape 102 forward a predetermined distance, such that datawriting may be resumed (or at least attempted) at an advanced locationon tape 102. In some embodiments, the distance tape 102 is advanced maybe programmable into tape drive 100. For example, the advancementdistance may be programmable into tape drive 100 firmware or software.

In certain embodiments, tape advancement module 114 may include servoelements and routines for monitoring and controlling the advancement ofmagnetic tape 102 in response to errors detected by error detectionmodule 112. For example, tape advancement module 114 servo may include alinear servo element located in tape head 110. Tape advancement module114 servo may use the linear servo element to track spool 108, includingthe advancement speed and/or the reading and writing speeds of magnetictape 102.

Furthermore, tape advancement module 114 servo may be configured toprocess magnetic tape 102. Tape 102 processing may include, e.g.,controlling track information on magnetic tape 102, writing servo trackinformation to magnetic tape 102, and reading servo track information onmagnetic tape.

Tape advancement module 114 servo, in coordination with tape head 110,may write and read servo tracks on magnetic tape 102, indicating wheredamaged and undamaged portions of tape 102 are located. In someembodiments, tape advancement module 114 servo may use servo tracks tomove directly to portions of tape 102 where error detection module 112has determined tape 102 is undamaged or where data has been written tomagnetic tape 102.

Tape head 110 may attempt to write data at advanced locations onmagnetic tape 102 and error detection module 112 may determine thesuccess of attempts to write data at advanced locations on tape 102.

Tape advancement module 114, tape head 110, and error detection module112 may cooperate to repeat the functions of advancing magnetic tape 102a predetermined distance, attempting to write data to magnetic tape 102,and determining if the attempted data write was successful followingeach unsuccessful data writing attempt. Tape head 110 may continue towrite data to magnetic tape 102 at an undamaged location afterdetermining that an attempted data write was successful.

Tape head 110, error detection module 112, and tape advancement module114 may cooperate to record and/or store tape location data 120 inmemory 118. In some embodiments, tape location data 120 is generatedbased on physical locations on magnetic tape 102 where error detectionmodule 112 determined that a writing error occurred (damaged-tapelocation data), or where data writing either was not interrupted or wasdetermined to be successful and resumed at an advanced location on tape102 (undamaged-tape location data).

In certain embodiments, tape head 110, error detection module 112,and/or tape advancement module 116 may cooperate with memory 118 toaccess and/or read damaged/undamaged-tape-location data 120, and/or usedamaged and/or undamaged tape location data 120 to automatically skipdamaged areas of magnetic tape 102.

Storage device 104 may be configured to identify various locations onmagnetic tape 102 where a data writing error were detected. Furthermore,in some embodiments, storage device 104 may be configured to identifylocations on magnetic tape 102 where no data writing error was detectedand where data writing resumed.

Tape advancement module 114 may be configured to skip over damagedportions of the magnetic tape 102 based on data stored in storage device104, data stored directly on magnetic tape 102, and/ordamaged/undamaged-tape-location data 120 stored in memory 120.

FIG. 2 illustrates a block diagram of an example information handlingsystem 200 for using magnetic tape 102 having damaged areas, inaccordance with certain embodiment of the present disclosure.

Information handling system 200 includes one or more tape drives 100communicatively coupled to one or more processors 202. Each processor202 may comprise any system, device, or apparatus operable to interpretand/or execute program instructions and/or process data, and mayinclude, without limitation, a microprocessor, microcontroller, digitalsignal processor (DSP), application specific integrated circuit (ASIC),or any other digital or analog circuitry configured to interpret and/orexecute program instructions and/or process data.

Each tape drive 100 may include a tape head 110 configured to write datato streaming magnetic tape 102, an error detection module 112 configuredto detect a data writing error at a first location, a tape advancementmodule 114 configured to interrupt data writing and advance tape 102forward a predetermined distance to a next location on magnetic tape 102in response to detecting a data writing error, and memory 118 configuredto store damaged/undamaged-tape-location data 120.

In operation, tape head 110 may attempt to write data at the nextlocation on the magnetic tape 102 and error detection module 112 may beconfigured to determine if the attempted data write was successful.

Tape advancement module 114, tape head 110, and error detection module112 may cooperate to repeat the functions of advancing magnetic tape 102a predetermined distance, attempting to write data to magnetic tape 102,and determining if the attempted data write was successful followingeach unsuccessful data writing attempt. Tape head 110 may then continueto write data to magnetic tape 102 after determining that an attempteddata write was successful.

Tape head 110, error detection module 112, and/or tape advancementmodule 116 may cooperate with memory 118 to store, access, and readdamaged/undamaged-tape-location data 120, and/or usedamaged/undamaged-tape-location data 120 to skip over damaged areas ofmagnetic tape 102.

FIG. 3 illustrates a flow chart of an example method 300 for usingmagnetic tape 102 having damaged areas, in accordance with certainembodiments of the present disclosure.

According to some embodiments, method 300 may begin at step 302.Teachings of the present disclosure may be implemented in a variety ofconfigurations of systems, including configurations of informationhandling system 200. As such, the preferred initialization point formethod 300 and the order of the steps 302-314 comprising method 300 maydepend on the implementation chosen.

At step 304, information handling system 200 may write data to streamingmagnetic tape 102.

At step 306, information handling system 200 may detect a data writingerror. In certain embodiments, detecting a data writing error onmagnetic tape 102 at step 306 may include performing a Cyclic RedundancyCheck (CRC).

As long as a data writing error is not detected, information handlingsystem 200 may record undamaged tape location data at step 314 and writedata to streaming magnetic tape 102 at step 304. In some embodiments,undamaged magnetic tape location data 120 may be recorded to memory 118at step 314.

If a writing error is detected at step 306, at step 308, informationhandling system 200 may record damaged magnetic tape location data. Insome embodiments, damaged magnetic tape location data 120 may berecorded to memory 118 at step 308.

At step 310, information handling system 200 may interrupt data writingand advance tape 102 forward a predetermined distance to a next locationon magnetic tape 102. In some embodiments, monitoring and controllingmagnetic tape 102 advancement forward a predetermined distance at step310 may include using a linear servo.

At step 312, information handling system 200 may attempt to write dataat the advanced location on magnetic tape 102. Information handlingsystem 200 may make one or multiple attempts to write data at thisadvanced location.

After attempting to write data to streaming magnetic tape 102 at theadvanced location on magnetic tape 102 at step 312, the method mayreturn to step 306 to determine if the attempted data write wassuccessful. In some embodiments, error detection at step 306 may includeusing a Viterbi detector to sample data tracks written to magnetic tape102.

If a data writing error is detected at step 306, information handlingsystem 200 may repeat the above steps 308-312. This process may berepeated, each time advancing to a further location on tape 102, untilinformation handling system 200 does not detect a data writing error atstep 306, at which point information handling system 200 may recordundamaged magnetic tape location data at step 314 and continue to writedata to streaming magnetic tape 102 at step 304.

Although FIG. 3 discloses a particular number of steps to be taken withrespect to method 300, method 300 may be executed with greater or lessersteps than those depicted in FIG. 3. In addition, although FIG. 3discloses a certain order of steps to be taken with respect to method300, the steps comprising method 300 may be completed in any suitableorder.

Method 300 may be implemented using information handling system 200 orany other system operable to implement method 300. In certainembodiments, method 300 may be implemented partially or fully infirmware and/or software embodied in computer-readable media.

FIG. 4 illustrates a flow chart of an example method 400 for accessingtape location data 120 and using such data 120 to skip damaged areas ofmagnetic tape 102, in accordance with certain embodiments of the presentdisclosure.

Teachings of the present disclosure may be implemented in a variety ofconfigurations of systems, including configurations of informationhandling system 200. As such, the preferred initialization point formethod 400 and the order of the steps 402-408 comprising method 400 maydepend on the implementation chosen.

At step 402, information handling system 200 may receive a request toread data from magnetic tape 102.

At step 404, information handling system 200 may access tape locationdata 120. In some embodiments, tape location data 120 is accessed frommemory 118.

At step 406, information handling system 200 may skip past damagedportions of tape 102 based on the accessed tape location data 120.

At step 408, information handling system 200 may begin reading data fromtape 102 after skipping past damaged portions.

Although FIG. 4 discloses a particular number of steps to be taken withrespect to method 400, method 400 may be executed with greater or lessersteps than those depicted in FIG. 4. In addition, although FIG. 4discloses a certain order of steps to be taken with respect to method400, the steps comprising method 400 may be completed in any suitableorder.

Method 400 may be implemented using information handling system 400 orany other system operable to implement method 400. In certainembodiments, method 400 may be implemented partially or fully infirmware and/or software embodied in computer-readable media.

Using the methods, systems, and devices disclosed herein, disadvantagesand problems associated with writing data to magnetic tape 102 havingdamaged areas may be substantially reduced or eliminated. For example,the methods, systems, and devices disclosed herein may provide theability to continue to advance magnetic tape 102 forward predetermineddistances in response to writing errors until undamaged portions of tape102 are located, thus allowing for data writing to continue and avoidingthe results of conventional approaches in which partially damagedmagnetic tapes are rendered unusable and discarded after a writingerror.

Although the present disclosure has been described in detail, it shouldbe understood that various changes, substitutions, and alterations canbe made hereto without departing from the spirit and the scope of thedisclosure as defined by the appended claims.

1. A method for using a magnetic tape having one or more damaged areas,the method comprising: writing data to streaming magnetic tape;detecting a data writing error at a damaged location on the magnetictape; in response to detecting a data writing error, interrupting thedata writing and advancing the magnetic tape forward a predetermineddistance; attempting to write data at a location on the magnetic tapecorresponding to the predetermined distance; determining if theattempted data write at the location on the magnetic tape wassuccessful; if it is determined that the attempted data write at thelocation on the magnetic tape was not successful, repeating the steps ofadvancing the magnetic tape forward a predetermined distance, attemptingto write data to the magnetic tape, and determining if the attempteddata write was successful, until an attempted data write is successful;and after determining that an attempted data write was successful,continuing to write data to the magnetic tape at an undamaged locationon the magnetic tape.
 2. A method according to claim 1, whereindetecting a data writing error at the damaged location on the magnetictape includes performing a Cyclic Redundancy Check.
 3. A methodaccording to claim 1, wherein determining if the attempted data writewas successful includes using a Viterbi detector to sample data trackswritten to the magnetic tape.
 4. A method according to claim 1, furthercomprising using a linear servo to monitor and control the advancementof the magnetic tape forward the predetermined distance.
 5. A methodaccording to claim 1, wherein the magnetic tape is housed in a LinearTape-Open (LTO) cartridge.
 6. A method according to claim 1, furthercomprising storing data identifying the damaged location on the magnetictape where the data writing error was detected.
 7. A method according toclaim 1, further comprising storing data identifying the undamagedlocation on the magnetic tape where data writing continued.
 8. A tapedrive for writing data to magnetic tape housed in a tape storage device,the tape drive comprising: a write head configured to write data tostreaming magnetic tape; an error detection module configured to detecta data writing error at a damaged location on the magnetic tape; a tapeadvancement module configured to interrupt data writing and advance themagnetic tape forward a predetermined distance in response to detectingthe data writing error; the write head configured to attempt to writedata at a location on the magnetic tape corresponding to thepredetermined distance; the error detection module configured todetermine if the attempted data write at the location on the magnetictape was successful; the tape advancement module, the write head, andthe error detection module configured to cooperate to repeat, thefunctions of advancing the magnetic tape a predetermined distance,attempting to write data to the magnetic tape, and determining if theattempted data write was successful following each unsuccessful datawriting attempt; and the write head configured to continue to write datato the magnetic tape at an undamaged location on the magnetic tape afterdetermining that an attempted data write was successful.
 9. A tape driveaccording to claim 8, wherein the error detection module for detecting adata write error performs a Cyclic Redundancy Check.
 10. A tape driveaccording to claim 8, wherein the error detection module for detecting adata write error includes a Viterbi Detector to sample data tracks. 11.A tape drive according to claim 8, wherein the tape advancement moduleincludes a linear servo for monitoring and controlling the advancementof the magnetic tape the predetermined distance.
 12. A tape driveaccording to claim 8, wherein the tape storage device housing themagnetic tape is a Linear Tape-Open (LTO) cartridge.
 13. A tape driveaccording to claim 8, further comprising a storage device configured toidentify the damaged location on the magnetic tape where the datawriting error was detected.
 14. A tape drive according to claim 8,further comprising a storage device configured to identify the undamagedlocation on the magnetic tape where no data writing error was detectedand data writing continued.
 15. An information handling systemcomprising: a processor; a tape drive coupled to the processor, the tapedrive including: a write head configured to write data to streamingmagnetic tape; an error detection module configured to detect a datawriting error at a damaged location on the magnetic tape; a tapeadvancement module configured to interrupt data writing and advance thetape forward a predetermined distance to; the write head configured toattempt to write data at a location on the magnetic tape correspondingto the predetermined distance; the error detection module configured todetermine if the attempted data write at the location on the magnetictape was successful; the tape advancement module, the write head, andthe error detection module configured to cooperate to repeat thefunctions of advancing the magnetic tape a predetermined distance,attempting to write data to the magnetic tape, and determining if theattempted data write was successful following each unsuccessful datawriting attempt; and the write head configured to continue to write datato the magnetic tape at an undamaged location on the magnetic tape afterdetermining that an attempted data write was successful.
 16. Aninformation handing system according to claim 15, wherein the errordetection module for detecting a data write error performs a CyclicRedundancy Check.
 17. An information handing system according to claim15, wherein the error detection module for detecting a data write errorincludes a Viterbi Detector to sample data tracks.
 18. An informationhanding system according to claim 15, wherein the tape advancementmodule includes a linear servo for monitoring and controlling theadvancement of the magnetic tape the predetermined distance.
 19. Aninformation handing system according to claim 15, further comprising astorage device configured to identify the damaged location on themagnetic tape where the data writing error was detected.
 20. Aninformation handing system according to claim 15, further comprising astorage device configured to identify the undamaged location on themagnetic tape where no data writing error was detected and data writingcontinued.